• Title/Summary/Keyword: gap element

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A Study for Rationalization of Lifting Lug Design of Ship Block (선박블록 탑재용 러그구조의 설계합리화를 위한 연구)

  • 함주혁
    • Journal of Ocean Engineering and Technology
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    • v.11 no.4
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    • pp.249-261
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    • 1997
  • A basic study on the lifting lug design has performed through the rational and systematic process. In order to evaluate the proper design-load distribution around lug eye investigation of contact force between lifting lug and shackle pin is performed using non-linear parametric analysis idealized by gap element models. Gap element modeling and nonlinear analysis procedures are illustrated and discussed based on MSC/NASTRAN. Some analysis and design guides are suggested through the consideration of several important effects such as stress distribution pattern, circumferential contact force distribution along the lug eye face, loading share rate between lug main plate and doubler, effect of loading direction, relation between applied force and deflection and size effect of shackle pin radius. Additionally optimum design studies are performed and general trends according to the variation of design parameters are suggested.

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Determination of the magnetic field in the air-gap of the linear stepper motor by finite element method (유한요소법에 의한 리니어스텝 모우터의 공극에서의 자계 분석)

  • 이승원;이병하
    • 전기의세계
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    • v.29 no.10
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    • pp.660-666
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    • 1980
  • The finite leement method is a effetive analysis technique for obtaining approximate solutions of continuum problems with boundary conditions. This paper deals with the programming for the application of this method and the preciser analysis of the magnetic field in the air gap of the linear stepper motor by the method. The finite element analysis based on the variational principle is adopted and the computer program for reducing input data and a large number of the memory words required by the system matrix is presented. The 2-dimensional analysis of the air gap is made and several cases according to varying the position are considered.

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Development of Multidimensional Gap Conductance Model for Thermo-Mechanical Simulation of Light Water Reactor Fuel (경수로 핵연료 열-구조 연계 해석을 위한 다차원 간극 열전도도 모델 개발)

  • Kim, Hyo Chan;Yang, Yong Sik;Koo, Yang Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.2
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    • pp.157-166
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    • 2014
  • A light water reactor (LWR) fuel rod consists of zirconium alloy cladding tube and uranium dioxide pellets with a slight gap between them. The modeling of heat transfer across the gap between fuel pellets and the protective cladding is essential to understanding fuel behavior under irradiated conditions. Many researchers have been developing fuel performance codes based on finite element method (FE) to calculate temperature, stress and strain for multidimensional analysis. The gap conductance model for multi-dimension is difficult issue in terms of convergence and nonlinearity because gap conductance is function of gap thickness which depends on mechanical analysis at each iteration step. In this paper, virtual link gap element (VLG) has been proposed to resolve convergence issue and nonlinear characteristic of multidimensional gap conductance. In terms of calculation accuracy and convergence efficiency, the proposed VLG model has been evaluated for variable cases.

A Simplified Method to Calculate the EMF Characteristics of Multi-disk Axial-gap PM Motor using 2-D & 3-D FEM

  • Kim, Young-Kwan;Lee, Ju
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.3
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    • pp.34-39
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    • 2008
  • The purpose of this paper is characteristic analysis of multi-disk axial-gap pm motor for turbo compressor. The axial-gap permanent magnet motor has shown a growing interest in high-speed application for its high-efficiency, compact size and low vibration characteristics due to core-less structure. To achieve high-power, the axial-gap PM motor has multi-disk structure of stator and rotor disk. Because of its complicated magnetic flux path, it is not easy to calculate a dynamic characteristics using finite element analysis. In this paper, the simplified 2-D unfolded model to predict EMF characteristic is presented. To verify thesuggested 2-D unfolded model analysis of back-EMF characteristic was calculated and compared 3-D finite element. Finally the proposed method is verified by experimental results and shows good agreement with test results.

The Natural Frequency of a Coaxial Cylindrical Shell with Fluid Coupling (유체 연성이 작용하는 동축 원통형 쉘의 고유진동)

  • 안병준;정경훈;이성철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.975-979
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    • 1994
  • The experimental and finite element studies of a coaxial cylindrical shell filled with liquid in the annular gap were performed to understand its vibration characteristics. Finite element analysis was achieved by using ANSYS code. Form the investigation of the changing trend of natural frequencies for the change of annular gap we know that the natural frequency of the coaxial cylindrical shell varies according to the mode shape. that is, in case of in-phase mode the natural frequency decrease as annular gap increase, but in case of out-of-phase mode the natural frequency increase. Finite element analysis results show the excellent agreement with the experimental results both in air and in water case, so that analysis on other cases with be possible without experiment.

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Analysis of the Technology Gap and Identification of R&D Priorities of Sports Industry in Korea (우리나라 스포츠산업의 기술수준 격차 분석 및 R&D 투자 우선순위 도출)

  • Rim, Myung Hwan
    • Journal of Information Technology Applications and Management
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    • v.24 no.2
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    • pp.97-112
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    • 2017
  • This paper aims to research the technology level of sports industry, through analyzing the technology gap between Korea and other major countries (USA, Europe, Japan, and China), and provide a list of technologies to be prioritized for R&D investment by conducting an analysis of the strategic importance of various element technologies. The results of the analysis showed that the technology level of Korean sports industry currently stands at 70.5% of the country with the most advanced technology (the USA), and that the technology gap amounts to 4.8 years. It was also found that the USA is the country with the most advanced technology (100%) at present, followed by Europe (91.1%), Japan (88.3%), Korea (70.5%), and China (61.2%). To reduce the technology gap, we established a Strategic Zone (SZ) and derived three element technologies including 'design and production technologies for sports and game equipment' in the $1^{st}$ tier, nine element technologies including '3D motion analysis and simulation technology' in the $2^{nd}$ tier, and four element technologies including 'fitness/health promotion and management technology' in the $3^{rd}$ tier. The significance of this research is that it included five major technology categories of the sports industry in its analysis, selected an expert on sports industry technologies using the delphi method. Therefore, the results of this study may be suitable for use as basic data in establishing the R&D strategy for the future development of the sports industry.

A Study on Attractive Force Characteristics of Glass Substrate Using Alumina Electrostatic Chuck by Finite Element Analysis (유한요소해석을 이용한 알루미나 정전척의 글라스 기판 흡착 특성 연구)

  • Lee, Jae Young;Jang, Kyung Min;Min, Dong Kyun;Kang, Jae Gyu;Sung, Gi Hyun;Kim, Hye Dong
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.4
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    • pp.46-50
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    • 2020
  • In this research, the attractive force of Coulomb type electrostatic chuck(ESC), which consisted of alumina dielectric, on glass substrate was studied by using the finite element analysis. The attractive force is caused by the high electrical resistance which occurs in contact region between glass substrate and dielectric layer. This research tries the simple geometrical modeling of ESC and glass substrate with air gap. The influences of the applied voltage, and air gap are investigated. When alumina dielectric with 1014 Ω·cm, 1.5 kV voltage, and 0.01 mm air gap were applied, electrostatic force in this work reached to 4 gf/㎠. This results show that the modeling of air gap is essential to derive the attractive force of the ESC.

The Effect of the Gap of Spline on the Deflection of Propeller Shaft (스플라인의 공차가 프로펠러 샤프트의 처짐에 미치는 영향)

  • Han, Dong-Seop;Lee, Seong-Wook;Kim, Yong;Han, Geun-Jo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.172-174
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    • 2007
  • A propeller shaft is the device which is used to transmit the power between two shafts in a vehicles, an industrial machinery, etc. The end of spline is worm due to the deflection of the propeller shaft, and a lifetime of it is reduced, because it for industrial machinery has the length of 2,500 mm, the weight of $300\;kg_{f},$ and the sliding distance of $\pm250\;mm.$ Accordingly in this study we analyzed the effect of the gap of spline on the deflection of a propeller shaft carrying out the finite element analysis, in order to determine the proper gap of spline to minimize the deflection of it. We adopt 10-kinds of gap of spline from 0.05 mm to 0.5 mm at interval of 0.05 mm as the design parameter for the finite element analysis and the centrifugal force as the load condition.

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Effects of Pounding at Expansion Joints of Concrete Bridges

  • Kim, Jong-In;Kim, Sang-Hoon
    • KCI Concrete Journal
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    • v.13 no.1
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    • pp.27-34
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    • 2001
  • This paper presents the results of a study on the effects of pounding at expansion joints of concrete bridges under earthquake ground motions. An engineering approach, rather than continuum mechanics, is emphasized. First, the sensitivity analysis of the gap element stiffness is performed. Second, usefulness of the analysis method for simulation of pounding phenomena is demonstrated. Third, the effects of pounding on the ductility demands measured in terms of the rotation of column ends are investigated. Two-dimensional FE analysis using a bilinear hysterestic model for bridge substructure joints and a nonlinear gap element for the expansion joint is performed on a realistic bridge with an expansion joint. Effects of the primary factors on the ductility demand such as gap sizes and characteristics of earthquake ground motion are investigated through a parametric study. The major conclusions are that pounding effect is generally negligible on the ductility demand for wide practical ranges of gap size and peak ground acceleration, but is potentially significant at the locations of impact.

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Analytical Investigation on Fundamental Electrical Characteristics of Large Air-gap Superconducting Synchronous Machine

  • Yazdanian, M.;Elhaminia, P.;Zolghadri, M.R.;Fardmanesh, M.
    • Journal of Magnetics
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    • v.18 no.3
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    • pp.260-267
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    • 2013
  • In this paper a general 2-D model of a large air-gap synchronous machine either with non-magnetic or magnetic core rotor is investigated and electrical characteristics of the machine are analytically calculated. Considering the general model, analytical equations for magnetic field density in different regions of the large air-gap machine are calculated. In addition, self and mutual inductances in the proposed model of the machine have been developed, which are the most important parameters in the electromagnetic design and transient analysis of synchronous machines. Finite element simulation has also been performed to verify the obtained results from the equations. Analytical results show good agreement with FEM results.